Lua Programming Help Thread

[emericaska8r]

this is what i found online:

*a - reads the entire file from the current position. ex: file.read("*a")

so i don't know what went wrong for you

[Nielkie]

For anyone who cares and develops in KDevelop,Kate,KWrite or KEdit, I have added all the PSP LuaPlayer functions to the SVN (much better than the default(which doesn't even support block comments or code collapsing) ) syntax highlighting script.

Put the lua.xml of your choice in ~/.kde/share/apps/katepart/syntax/ or /opt/kde/share/apps/katepart/syntax/ (depending on your distribution)

Please post any suggestions/problems/comments.

[BJ2]

hello, i have only just started learning lua yesterday and am VERY new to it so please don't be harsh.
i try to add a background to my simple text and it doesn't work, this is my lua script:

red = Color.new(255, 0, 0)
blue = Color.new(0, 0, 255)
green = Color.new(0, 255, 0)
white=Color.new(255,255,255)

background = Image.load("background.png")
screen.flip()
screen.waitVblankStart()

screen:print(130, 130, "background", white)
screen:print(100, 200, "SUPID BACKGROUND ISN'T WORKING!!!", red)
screen.flip()

while true do
screen.waitVblankStart()
end

i know that this is probably i very easy answer for most of you but it isn't working for me and i need to know why. i have a 480 by 272 pivture in the same folder called background and it is a .PNG picture

thanks for the help

[SG57]

Aye, it is a simple mistake. Common among new developers as the tutorials are misleading (IMO). There are a few mistakes ultimately making it not do as you wish. For one, you aren't ever really blit'ing the image ,rather just loading it into the var 'background' and printing the var's name ;). Secondly, you have an even number of screen.flip()'s therefore making anything you wish to actually display 'hidden'. It's best to only have 1 screen.flip() and 1 screen.waitVblankStart() (unless you have specific needs for them). Since you aren't doing anything needing to continually check for something, you just need an indefinate delay at the end, nothing more :)

red = Color.new(255, 0, 0)
blue = Color.new(0, 0, 255)
green = Color.new(0, 255, 0)
white=Color.new(255,255,255)

background = Image.load("background.png")

screen:blit(0,0,background)

screen.waitVblankStart()
screen.flip()

while true do
end

P.S. Use [ code][/ code] tags as well, they prevent smilies and preserve tabs) And yeah, if you do get flamed, it's no biggie, ask one of the vet's to look over the situation to see what's really what ;)

[BJ2]

thanks, but it still doesn't work, i even tried to copy and paste the code you wrote. i also fixed the

white =Color.new(255, 255, 255)

so there was a space between the = and the C.

btw, im using "luaplayerwindows-0.20"
lua for the computer. i dont yet know how to make it an eboot

[SG57]

What's your error exactly? You probably don't have the background.png in the same folder. The space between the = and C isn't an error. And you don't make Lua scripts into EBOOTs ;) You get the Lua Player for PSP and run the script just like on windows.

[BJ2]

kk, thaks a bunch for the help SG57. i finaly figured out how to fix, it was i nooby mistake of having the pic a different format to what i wrote.
thanks again :)

and i figured out my lua for PC doesn't work (can't do anything except text on a black background ), cause the exact thing works on my psp.

anyone got a link to a Lua player for PC that works properly,
thanks

[Anti-QuickJay]

http://luaplayer.org/downloads/lp20/...ndows-0.20.zip

[Highsight]

Does anyone know how I can blit 25 10x10 images over 3D objects? For some reason, whenever I try to do it, it goes behind the 3D model. :/

[Nielkie]

I don't think you can. However you can compromise by bliting the Image as a 3D model (two textured triangles)

That problem will be fixed in the next version of Lua Player.

[Judas]

Does anyone know how I can blit 25 10x10 images over 3D objects? For some reason, whenever I try to do it, it goes behind the 3D model. :/

I don't know anything about 3D yet, but I would guess that you just have to make sure you're blitting the images after you blit your textures.

[Highsight]

I don't think you can. However you can compromise by bliting the Image as a 3D model (two textured triangles)

That problem will be fixed in the next version of Lua Player.

That sounds like it could work fine, the only problem is I need to ensure that it stays exactly in the top left corner of the screen, rather than staying somewhere on the 3D plane. Any suggestions on how I could do that?

[Grimfate126]

i dunno if lua supports depth testing, but try this: (this is the 'traditional' way to do in in the GU)

1. turn depth test on
2. do all 3d stuff
3. turn depth test off
4. blit image to top right corner.

done

[Highsight]

i dunno if lua supports depth testing, but try this: (this is the 'traditional' way to do in in the GU)

1. turn depth test on
2. do all 3d stuff
3. turn depth test off
4. blit image to top right corner.

done

Sadly, that is what I've been trying to do, I guess it doesn't support depth testing. :/

[BlackShark]

Where can i get information on how to compile the oslib(oldschool library) on windows? ive searched the docs and googled it to the bone, any body know?

[Judas]

Shouldn't that question be in C help? Anyway, there's probably some documentation in the readme. If not, check the Makefile, it'll be there.

[BlackShark]

whoops, wrong topic :S sorry

[Merick]

That sounds like it could work fine, the only problem is I need to ensure that it stays exactly in the top left corner of the screen, rather than staying somewhere on the 3D plane. Any suggestions on how I could do that?

If you leave out the Gu.translate statement when drawing the image, then the coordinates in the model table will be relative to the top corner instead of the center of the screen. For an example, take a look at this function (the gu start and end calls aren't use inside the function because if you use this to draw a lot of images it works faster to start and stop the gu before and after doing all the calls to this function):

function Gu.blit(x, y, image, scale, flip)
	
	if scale then
		if type(scale) == "string" then 
			flip = scale
			scale = 1
		else
			scale = (scale/100) 
		end
	end
	
	if flip then
		if flip == "H" then
			x_start = image:width()
			y_start = 0
			x_end  = 0
			y_end = image:height()
		elseif  flip == "V" then
			x_start = 0
			y_start = image:height()
			x_end  = image:width()
			y_end = 0
		elseif flip == "HV" then
			x_start = image:width()
			y_start = image:height()
			x_end = 0
			y_end = 0
		end
	else
		x_start = 0
		y_start = 0
		x_end = image:width()
		y_end = image:height()
	end
	
	temp = {
	{x_start, y_start, x, y, 0},
	{x_end, y_end, (image:width()*scale)+x, (image:height()*scale)+y, 0}
	}
	Gu.enable(Gu.TEXTURE_2D)
	Gu.texImage(image)
	Gum.drawArray(Gu.SPRITES, Gu.TEXTURE_32BITF+Gu.VERTEX_32BITF+Gu.TRANSFORM_2D, temp)
end

[Highsight]

Well, in that case, it looks like that function you just posted should do it! But I must be using it wrong, whenever I try to use it, nothing shows up. when I use it I enter in "Gu.blit(0, 0, (image name), 100, false)"

Did I do something wrong? :/

[Merick]

The last argument, "flip" is not a boolean, it takes one of 3 strings: "H" to flip horizontal, "V" to flip vertical, and "HV" to flip it both ways. If you don't want to flip the image just leave it out: "Gu.blit(0, 0, (image name), 100)"

[Highsight]

Ok, I figured it out, I just had it outside of the gu.start method. XD It is almost working, it is bliting as a 3D object with a texture, but it is still behind all the other 3D objects. Any ideas how to fix that? As soon as that is done, it will all work!

[Merick]

about the only thing I can think of for that is to mess around with the z coords inside the model table

[Highsight]

HAHA! That did it! I just made the z values 1000000000000000000. Thanks so much Merick! Expect your name in my MazeGen credits. ;)

[j3r3mie]

Is it possible to play a sound when you hit a button.

[eldiablov]

yes it is

[FaT3oYCG]

request - conversions

i would like as many people as possible to help with this

i would like and and all of the conversions for lua code to c and vice versa

e.g.

screenrint = pspDebugScreenPrintf

and so on for a program that i am makeing to help people who know lua to learn c as i do not yet know c myself i cannot convert them all and even if i could i would probably forget some

the program will help people who know lua to learn c and even if they dont want to lean it it will help them to compile their lua programs into c code

which would be useful for every one and more people would learn lua and c

please if you have any conversions for me or have any suggestions of how to do some of the conversions please pm me !!!!!!!!!

[Anti-QuickJay]

the program will help people who know lua to learn c and even if they dont want to lean it it will help them to compile their lua programs into c code

You can compile your LUA scripts into C files? How? :ROFL:

[Merick]

I'm don't know how to do this with C, however on the FreeBasic messageboard one of the guys posted a macro that will cause a file (of any type) to be compiled into the exe. When the program is run, the data from that file is loaded into a memory buffer. Using this, I was able to compile some scripts into my FreeBasic programs and run them with lual_loadbuffer and lua_pcall

[j3r3mie]

CAn some one put the code for have a sound play when i push a button and an ohther one when i push another button.

[Nielkie]

Can't you code it yourself, it'll take like 5 lines.